1 files changed, 162 insertions, 0 deletions
diff --git a/Jellyfin.Drawing.Skia/SplashscreenBuilder.cs b/Jellyfin.Drawing.Skia/SplashscreenBuilder.cs
new file mode 100644
index 000000000..8b6942be0
--- /dev/null
+++ b/Jellyfin.Drawing.Skia/SplashscreenBuilder.cs
@@ -0,0 +1,162 @@
+using System;
+using System.Collections.Generic;
+using MediaBrowser.Controller.Drawing;
+using SkiaSharp;
+
+namespace Jellyfin.Drawing.Skia
+{
+    /// <summary>
+    /// Used to build the splashscreen.
+    /// </summary>
+    public class SplashscreenBuilder
+    {
+        private const int Rows = 6;
+        private const int Spacing = 20;
+
+        private readonly SkiaEncoder _skiaEncoder;
+
+        private Random? _random;
+        private int _finalWidth;
+        private int _finalHeight;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SplashscreenBuilder"/> class.
+        /// </summary>
+        /// <param name="skiaEncoder">The SkiaEncoder.</param>
+        public SplashscreenBuilder(SkiaEncoder skiaEncoder)
+        {
+            _skiaEncoder = skiaEncoder;
+        }
+
+        /// <summary>
+        /// Generate a splashscreen.
+        /// </summary>
+        /// <param name="options">The options to generate the splashscreen.</param>
+        public void GenerateSplash(SplashscreenOptions options)
+        {
+            _finalWidth = options.Width;
+            _finalHeight = options.Height;
+            var wall = GenerateCollage(options.PortraitInputPaths, options.LandscapeInputPaths, options.ApplyFilter);
+            var transformed = Transform3D(wall);
+
+            using var outputStream = new SKFileWStream(options.OutputPath);
+            using var pixmap = new SKPixmap(new SKImageInfo(_finalWidth, _finalHeight), transformed.GetPixels());
+            pixmap.Encode(outputStream, StripCollageBuilder.GetEncodedFormat(options.OutputPath), 90);
+        }
+
+        /// <summary>
+        /// Generates a collage of posters and landscape pictures.
+        /// </summary>
+        /// <param name="poster">The poster paths.</param>
+        /// <param name="backdrop">The landscape paths.</param>
+        /// <param name="applyFilter">Whether to apply the darkening filter.</param>
+        /// <returns>The created collage as a bitmap.</returns>
+        private SKBitmap GenerateCollage(IReadOnlyList<string> poster, IReadOnlyList<string> backdrop, bool applyFilter)
+        {
+            _random = new Random();
+
+            var posterIndex = 0;
+            var backdropIndex = 0;
+
+            // use higher resolution than final image
+            var bitmap = new SKBitmap(_finalWidth * 3, _finalHeight * 2);
+            using var canvas = new SKCanvas(bitmap);
+            canvas.Clear(SKColors.Black);
+
+            int posterHeight = _finalHeight * 2 / 6;
+
+            for (int i = 0; i < Rows; i++)
+            {
+                int imageCounter = _random.Next(0, 5);
+                int currentWidthPos = i * 75;
+                int currentHeight = i * (posterHeight + Spacing);
+
+                while (currentWidthPos < _finalWidth * 3)
+                {
+                    SKBitmap? currentImage;
+
+                    switch (imageCounter)
+                    {
+                        case 0:
+                        case 2:
+                        case 3:
+                            currentImage = SkiaHelper.GetNextValidImage(_skiaEncoder, poster, posterIndex, out int newPosterIndex);
+                            posterIndex = newPosterIndex;
+                            break;
+                        default:
+                            currentImage = SkiaHelper.GetNextValidImage(_skiaEncoder, backdrop, backdropIndex, out int newBackdropIndex);
+                            backdropIndex = newBackdropIndex;
+                            break;
+                    }
+
+                    if (currentImage == null)
+                    {
+                        throw new ArgumentException("Not enough valid pictures provided to create a splashscreen!");
+                    }
+
+                    // resize to the same aspect as the original
+                    var imageWidth = Math.Abs(posterHeight * currentImage.Width / currentImage.Height);
+                    using var resizedBitmap = new SKBitmap(imageWidth, posterHeight);
+                    currentImage.ScalePixels(resizedBitmap, SKFilterQuality.High);
+
+                    // draw on canvas
+                    canvas.DrawBitmap(resizedBitmap, currentWidthPos, currentHeight);
+
+                    currentWidthPos += imageWidth + Spacing;
+
+                    currentImage.Dispose();
+
+                    if (imageCounter >= 4)
+                    {
+                        imageCounter = 0;
+                    }
+                    else
+                    {
+                        imageCounter++;
+                    }
+                }
+            }
+
+            if (applyFilter)
+            {
+                var paintColor = new SKPaint
+                {
+                    Color = SKColors.Black.WithAlpha(0x50),
+                    Style = SKPaintStyle.Fill
+                };
+                canvas.DrawRect(0, 0, _finalWidth * 3, _finalHeight * 2, paintColor);
+            }
+
+            return bitmap;
+        }
+
+        /// <summary>
+        /// Transform the collage in 3D space.
+        /// </summary>
+        /// <param name="input">The bitmap to transform.</param>
+        /// <returns>The transformed image.</returns>
+        private SKBitmap Transform3D(SKBitmap input)
+        {
+            var bitmap = new SKBitmap(_finalWidth, _finalHeight);
+            using var canvas = new SKCanvas(bitmap);
+            canvas.Clear(SKColors.Black);
+            var matrix = new SKMatrix
+            {
+                ScaleX = 0.324108899f,
+                ScaleY = 0.563934922f,
+                SkewX = -0.244337708f,
+                SkewY = 0.0377609022f,
+                TransX = 42.0407715f,
+                TransY = -198.104706f,
+                Persp0 = -9.08959337E-05f,
+                Persp1 = 6.85242048E-05f,
+                Persp2 = 0.988209724f
+            };
+
+            canvas.SetMatrix(matrix);
+            canvas.DrawBitmap(input, 0, 0);
+
+            return bitmap;
+        }
+    }
+}